Cylinder piston unit, especially for steam engines

ABSTRACT

The invention relates to a cylinder piston unit, especially for steam engines with expansion by heat influx, which is constructed as follows: a piston guided in the cylinder element has a displacer, a heating device is mounted on the cylinder element for the stroke area of a non-compacting displacer, the working medium is supplied in a vapour or liquid state in the area of the upper dead point, the expanded working medium is discharged at least in the area of the lower dead point. A pore burner is assigned to the cylinder piston unit in an advantageous mamler. To this end, the invention provides for the heat transfer sections (B, C) of a pore burner ( 50 ) which surrounds the cylinder head ( 43 ) along part of its height to be arranged at the level of the warm section ( 41 ) of the cylinder in the stroke area of the displacer ( 3 ) and at the level of the cylinder head ( 43 ).

The invention relates to a cylinder-piston unit in particular for steampower engines with expansion by heat influx, as defined in theintroductory part of the main claim.

Known is a steam power engine with a cylinder-piston unit according toDE-PS 828 988, with expansion by feed of heat. The piston has a warmhead, which is insulated against its inner side. The feed of heat to thecylinder-piston element takes place via cylinder ribs by means of anopen burner in the stroke area of the insulated warm head and thecylinder head with the compression chamber. The steam is generateddirectly in the heated cylinder by metered injection of water. Theoutlet for the expanded steam is formed by slots that are released bythe piston in the zone of the lower dead point.

A pore burner for substantially NOx-free combustion is known from patentdocument DE 43 22 109 A1. Stabilization and limitation of thetemperature in the course of combustion is achieved through arrangingparticles in layers varying based on fine to coarse pores, in steps fromthe inlet to the outlet of the fuel gas, which assures low-pollutantcombustion. This type of burner has a high power density based on itsstructural volume, whereby the document describes its application as agenerator of hot water or of steam.

The invention is based on the problem of feeding the cylinderpiston unitof the steam power engine directly with heat by means of a pore burneradmitting heat directly on the cylinder head and expansion chamber.

Said problem is solved by the features specified in the characterizingpart of the independent claim and in the dependent claims. By means ofthe proposed type of construction, a complex feed of heat to theoperating medium is achieved for the entire operating space, on the onehand, as well as low-loss heat transfer to said space, on the other.

Pore burners work with relatively low combustion temperatures and,because of their structure, permit the development of heat bridgesdirectly leading to the cylinder-piston unit. The low combustiontemperature level is suited for the transfer of heat into the operatingprocess of a steam engine with expansion by heat influx, on the onehand, and assures low-pollutant combustion, on the other.

The features of the dependent claims are explained in greater detail inthe description in connection with their effects.

An exemplified embodiment of the invention and further developments ofsaid embodiment according to the dependent claims are described in thefollowing with the help of a drawing, in which:

FIG. 1 is a longitudinal section through a cylinder-piston unit with adisplacer, and with feed of heat by a ring-shaped pore burner; and

FIG. 2 is a top view of a polygonal displacer, showing a cross sectionthrough the cylinder-piston unit with an enlarged surface of thedisplacer and the warm section of the cylinder, as well as thecombustion sections of the pore burner.

FIG. 1 shows a cylinder-piston unit 1 with a piston 2 and a displacer 3,as well as the overall feed of heat to the operating medium in theentire operating space 5. A special pore burner 50 with the combustionsection A is employed for this purpose. The heat transfer sections B andC surround the lower part of the cylinder head 43 and the cylinder 1 inthe stroke area 41 of the displacer 3. The guide piston 2 supports thesealing rings 21 as well as a displacer 3, which is secured in aheat-insulated manner. Said displacer is connected with a crankshaft(not shown) with a connecting rod, and guided in the cylinder bore 4 ina warm and in a cold cylinder section 41; 46.

The displacer 3 preferably has an absorption or reflection surface 31,and a heat storage layer 32 and an insulation layer 33 are preferablylocated under said surface. With the design features of displacer 3described above, storage of heat is achieved, on the one hand, andreflection of heat for heating the charge between the displacer 3 andthe inner surface of the cylinder section 41 is accomplished, on theother. Said design ensures corrective transfer of heat with highefficiency by means of the flow within the area of the cylinder, andthrough hot walls of the cylinder section 41 and the cylinder head 43.

The radial ribs 44 and/or needle- or bridge-shaped, radial attachmentsare arranged on the cylinder jacket 42 in the cylinder section 41 of thedisplacer 3, or additionally also on the cylinder head 43, said radialattachments being offset relative to each other. The heat transfersections B and C of the pore burner 50 are formed between the outwardlyclosed sectors of said attachments. The cylinder jacket 42 and thecylinder head 43, in their form described above, may be produced in theform of cast or sintered parts, and/or may have a coating for enlargingthe heat-transferring surface area.

Within its stroke area, the displacer 3 is guided with play parallelwith the warm cylinder section 41 surrounding it, and it has a crosssection that becomes smaller in the direction of the cylinder head 43.For optimal transfer of heat to the operating medium, which is presentin the operating chamber 5 and in the gap between the warm cylindersection 41, the cylinder head 43 and the displacer 3, the surfacescomplementing each other may be designed like a polygon. The hottestheat transfer section B is associated with said area.

In connection with the cylinder bore 4, which is heated from theoutside, the warm cylinder section 41 in the stroke area of thedisplacer 3, and the cylinder head 43 are advantageously designed asradiators, the radiation of which is in the range of the absorptionspectrum of the operating medium.

The pore burner 50 is associated with the cylinder head 43. The poreburner extends in the form of a ring, covering part of the cylinder head43.

The heat transfer sections B and C of the pore burner 50, and the steamgenerator 6 are usefully surrounded on the outside by an insulatinglayer 51.

The outer side of the heat transfer sections C on the cylinder jacket 42is enclosed by a steam generator 6, or preheater. The combustion gasesof the pore burner 50 are discharged from the space surrounding the heatgenerator 6.

Advantageously, the pipe ducts 7 of a superheating stage are arrangedbetween the heat transfer sections B and C and/or in the cylinder jacket42, preferably in the radial ribs 44 of the latter, said ribs extendingparallel with the axis of the cylinder jacket 42.

In the cold cylinder section 46 at the end of the stroke area of theguide piston 2, the outlet duct 11 discharges with windows that arecovered by the sealing rings 21 of the guide piston 2.

List of Reference Numerals and Letters:

1 Cylinder-piston unit;

2 Guide piston;

21 Ring seals

1 Displacer

31 Absorption or reflection surface;

32 Heat storage layer;

33 Insulating layer;

4 Cylinder bore;

41 Warm cylinder section/stroke area of displacer 3;

42 Cylinder jacket;

43 Cylinder head;

44 Ribs;

46 Cold cylinder section/stroke area of guide piston 2

5 Operating chamber;

50 Pore burner;

51 Insulating layer;

5 Steam generator;

6 Pipe ducts of a superheater hood;

11 Outlet duct;

A Combustion section of 50;

B Heat transfer section;

C Heat Transfer section.

What is claimed is:
 1. A cylinder-piston unit for steam engines withexpansion by heat influx comprising: a piston guided in a cylinderelement, said cylinder element comprising a cylinder head (43) and acylinder jacket (42); a non-compressing displacer disposed in saidcylinder jacket (42); a heating device arranged on the cylinder elementfor a stroke area of said non-compressing displacer; a pore burner (50)disposed on said cylinder head (43); and heat transfer sections (B;C)surrounding said cylinder head (43) over part of its height and arrangedon a warm cylinder section (41) in the stroke area of said displacer(3); wherein operating medium fed in the gaseous or liquid state into azone of the upper dead point and wherein the expanded operating mediumis discharged in an area of the lower dead point.
 2. The cylinder-pistonunit according to claim 1, wherein said cylinder section (41) comprisesat least one of the following: radial ribs (44), needle-shaped radialattachments, and bridge-shaped radial attachments, arranged in thestroke area of the displacer (3), with heat transfer sections (B;C) ofsaid pore burner (50) arranged between sectors of said attachments, saidsectors being closed outwardly.
 3. The cylinder-piston unit according toclaim 1, wherein said cylinder section (41) and said cylinder head (43)are cast or sintered parts.
 4. The cylinder-piston unit according toclaim 1, wherein said cylinder piston section (41), said cylinder head(43) and said displacer (3) individually or in series have a coating forenlarging the heat transfer surface area.
 5. The cylinder-piston unitaccording claim 1, wherein hot zones and said heat transfer sections(B;C) are outwardly surrounded by an insulating layer (51).
 6. Thecylinder-piston unit according to claim 1, wherein an outer side of saidpore burner (50) surrounding said cylinder head (43) and said cylinderjacket (42), with its heat transfer sections (B;C), is enclosed by asteam generator (6) or a preheater.
 7. The cylinder-piston unitaccording to claim 2, wherein, said heating device comprises a pluralityof pipe ducts (7) arranged in or between at least one of the following:said heat transfer sections (B;C) of said pore burner (50) and saidradial ribs (44) of said cylinder jacket (42), said radial ribsextending parallel with the axis of said cylinder jacket (42).
 8. Thecylinder-piston unit according to claim 1, wherein inner sides of saidcylinder jacket (42) and said cylinder head (43) are designed asradiators, the radiation of which is in the range of the absorptionspectrum of the operating medium.
 9. The cylinder-piston unit accordingclaim 1, wherein said displacer is guided with play versus an innersurface of said cylinder element, wherein said inner surface of saiddisplacer (3) is designed as an absorption or a reflection surface forthe radiation of said cylinder jacket (42) and said inner surface has aheat storing mass (32) inwardly surrounded by an insulating layer (33).10. The cylinder-piston unit according to claim 1, wherein saiddisplacer (3), said cylinder jacket (42), said warm cylinder section(41) and said cylinder head (42) are provided with complimentarypolygonal structures.
 11. The cylinder-piston unit according claim 2,wherein said ribs (44) are incorporated by casting or sintering on saidcylinder jacket (42), said ribs being offset relative to one another.